JP3220336B2 - Lifting and lowering control device for working equipment of agricultural tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a ground machine having a three-point link mechanism mounted on a traveling machine body, and the link mechanism being driven by a lift cylinder, so that the ground machine can be moved up and down. The present invention relates to a lifting control device for a working device of an agricultural tractor.

[0002]

2. Description of the Related Art Heretofore, when a ground working apparatus is raised with respect to a traveling machine body, the operation is always performed at a constant oil supply amount (per unit time).

[0003]

However, in the three-point link mechanism, the link ratio increases as the ground work device rises, and the amount of rise of the ground work device relative to the amount of expansion and contraction of the lift cylinder tends to increase. . Therefore, when comparing the case of raising from a lower position and the case of raising from a higher position, as shown in FIG.
When lubrication was performed against the internal pressure of the lift cylinder as much as the internal pressure was increased, the pressure fluctuated greatly, and shocks and shears were likely to occur. The purpose of the present invention is
It is another object of the present invention to provide a control system capable of performing an ascending operation with less shock or shaking even when ascending from a high position.

[0004]

According to a characteristic feature of the present invention , a supply means for supplying oil to the lift cylinder is provided, and the amount of oil supplied per unit time by the supply means is set such that a rising start position of the ground working device is high. When in position,
There is provided an adjusting means for reducing the number as compared with the case where it is at a lower position, and its operation and effect are as follows.

[0005]

In other words, in the case of raising from a high position by the adjusting means, the amount of supplied oil is reduced and the raising operation is performed with less shock or the like. The amount of oil is increased so that a quick rise can be performed even when the link ratio is small.

[0006]

As a result, it is possible to perform the ascending operation with less shock or the like regardless of the ascending start position of the ground work apparatus.

[0007]

[0008]

【Example】

[First Embodiment] As shown in FIG. 1, a pair of left and right lower links 1 and a top link 2
A rotary tilling device 4 is connected via a point link mechanism 3 so as to be able to ascend and descend to form a farm tractor. Lift cylinder C provided above transmission case 5 of the traveling aircraft
The lower link 1 is lifted and supported via a lift rod 7 by a pair of left and right lift arms 6 driven to move up and down by Y1, and the tilling apparatus 4 is driven to move up and down by driving a lift cylinder CY1 to expand and contract. It is. Also, one of the lift rods 7 is configured to be extendable and contractible by a rolling cylinder CY2.
By driving Y2, the left and right inclination posture of the tilling device 4 with respect to the machine body can be changed. The top link 2 is attached to the traveling body via a large-sized bracket 18 and has a short overall length. When the cultivator 4 is raised, the link ratio increases, and a parallel quadruple link mechanism is employed. The tilling apparatus 4 is arranged to be closer to the fuselage near the ascending limit as compared with the case in which it is performed.

This agricultural tractor has an automatic tilling depth control for driving and controlling the lift cylinder CY1 so that the tilling depth of the rotary tilling device 4 is maintained at a set value in the tilling operation, and the position lever of the tilling device 4 with respect to the machine is controlled by a position lever. Position control for driving and controlling the lift cylinder CY1 to maintain the height set at 8 and rolling control for maintaining the inclined state of the tilling device 4 in the set state regardless of the lateral inclination of the traveling machine body are performed. It is configured as follows. That is, as shown in FIG. 2, a potentiometer-type position setting device 9 for detecting the operating position of a position lever 8 which can be pivoted back and forth provided in the aircraft control section, and the rotation angle of the lift arm 6 are set to the pair of the tilling device 4. Potentiometer-type lift arm angle sensor 10, which detects as the body angle,
A potentiometer-type tillage depth detection sensor 12 for detecting a vertical swing amount corresponding to a tillage depth of a rear cover 11 provided at a rear portion of the tillage device 4 so as to be swingable about a horizontal axis X, a potentiometer provided in a body control section. Each output of the mold depth setting device 13 is a control device 1 equipped with a microcomputer.
4 given. When the operation position of the position lever 8 is in the position operation area A, the control device 14 performs the position control, and when the operation position of the position lever 8 is in the cultivation depth control area B, the control device 14 performs the cultivation depth control. That is, position control is performed by switching control of the electromagnetic proportional control valve V1 for the lift cylinder CY1 so that the setting value of the position setting device 9 and the detection value of the lift arm angle sensor 10 match, and the detection value of the tillage depth detection sensor 12 is controlled. The automatic plowing depth control is performed by switching and controlling the electromagnetic proportional control valve V <b> 1 so that the value matches the set value of the plowing depth setting device 13.

Next, the rolling control of the tillage device will be described. The traveling body is provided with an inclination sensor 15 for detecting the left-right inclination angle from the absolute horizontal posture, and a potentiometer-type inclination setting device 16 is provided in the control section, and the detected value of the lift arm angle sensor 10 is equal to or more than a predetermined set value, and When the device 4 rises significantly above the ground, the control device 14 controls the electromagnetic proportional control valve V2 for the rolling cylinder CY2 so that the tilling device 4 is in a parallel position with respect to the body so that the amount of expansion and contraction is predetermined by mechanical characteristics. And executes the parallel control. The operating state of the rolling cylinder CY2 is linked via an operation wire (not shown), and is detected and fed back by a potentiometer type stroke sensor 17 disposed on the machine body side. When the detected value of the lift arm angle sensor 10 is equal to or less than a predetermined set value and the tilling device 4 is in the working ground state, the electromagnetic proportional control valve is set so that the tilling device 4 is set to the posture set by the tilt setting device 16. V2 is switched to execute rolling control.

Next, the refueling control for the lift cylinder CY1 for raising and lowering the rotary tilling device 4 will be described. As described above, in the three-point link mechanism 3,
Since the top link 2 is shorter, the so-called link ratio increases as the tilling device 4 moves upward with respect to the traveling machine body, and the ratio of the tilling device 4 moving up and down with respect to the amount of expansion and contraction of the lift cylinder CY1 increases. Therefore, the higher the ascending start position is, the higher the cylinder internal pressure becomes, and if the refueling speed is the same, a shock is likely to occur. Therefore, the following control mode is adopted. As shown in FIG. 3, when there is a rising command (# 1), the height (c, b, a) of the rising start position is determined by the lift arm angle sensor 10 (# 2). Is reduced (# 3-5). Then, as shown in FIG. 5 to FIG. 7, the fluctuation of the cylinder internal pressure is suppressed irrespective of the rising start position, and the shock and the shearing phenomenon are reduced. The means for changing the flow rate in accordance with the ascending start position is referred to as a supply oil amount adjusting means, and the electromagnetic proportional control valve V1 mainly performs its function. As a control form, the current is controlled by the PWM method to adjust the supply amount.

[Second Embodiment] Next, a description will be given of a control mode for reducing the number of tilling depressions as shown in FIG. 11 when switching from the plowing depth control to the position control. That is, when lifting the tillage device 4 above the ground surface by the position control from the tillage depth control state, the lift cylinder C
The refueling amount to Y1 is set to be smaller than that in the case where the ascending operation is performed by the normal position control. Therefore, FIG.
As shown in FIG. 5, when the position control is started by operating the position lever 8 from the plowing depth control state (# 11, # 12), the position set value P becomes larger than the plowing depth target value D. It is determined whether it is large or not, and it is checked whether or not the tillage device 4 comes out on the ground surface (# 13). Then, when it comes out on the ground surface, the amount of refueling is reduced and the vehicle slowly rises from the plowing position until it leaves the ground surface. The position leaving the ground surface is determined from the lift arm angle θ _R at the time when the position control is started and the lift arm angle θ _G when the tilling claw separates from the ground surface from the cultivation depth target value D. It is understood by. When the vehicle escapes from the ground surface, a rapid ascent by the refueling amount of the ordinary position control is performed (# 14, 16, 17, 18). If the vehicle is not separated from the ground surface, rapid ascending and descending by the refueling amount of the normal position control is performed (# 15).

Next, a method of detecting a short circuit of the electromagnetic proportional control valve V1 will be described. As shown in FIG. 8, a current detection resistor 21 is connected to the ground side of the coil 20 of the electromagnetic proportional control valve V1, and a short-circuit state is detected by detecting a voltage across the resistor 21. That is, when the electromagnetic proportional control valve V1 is driven, PWM control is performed,
In determining the duty ratio, control is performed so that the integrated voltage for one cycle of the both-ends voltage converges to a target value, and a short-circuit state is detected when the duty ratio is smaller than the target current. However, the duty ratio did not become small even when a short circuit occurred due to the voltage of the battery or the resistance of an electric wire or the like. Therefore, the detection voltage is sampled at a constant period (about 10 msec), and if the detection voltage is zero or if the constant voltage continues for a certain period of time as shown in FIG. 10, it is determined that a short circuit has occurred, and an alarm is issued. . The detection voltage in the normal case is as shown in FIG.
The current value is indicated by the area of the detected voltage.

[Another Embodiment] Another embodiment of the first embodiment will be described. (1) In the configuration in which the supply oil amount is adjusted according to the ascending start position, the adjustment is performed in three stages in the first embodiment, but may be performed in two stages.
The classification may be increased to four stages and five stages, and may be finally performed without steps. In the case where the operation is performed in two stages, it may be classified into a case where the ascending start position is within the field surface and a case where the ascending start position is above the field surface. (2) As means for adjusting the oil supply amount, the electromagnetic proportional control valve V1 was used. However, another means using another pressure reducing valve, an electromagnetic valve, or the like, or a variable type flow pump was used. Is also good. (3) The supply means for supplying oil to the lift cylinder CY1 includes the electromagnetic proportional control valve V1 and the hydraulic pump. Another embodiment will be described with respect to the second embodiment. (4) As a method of detecting whether or not the tillage device 4 is separated from the ground surface, a detection value of the tillage depth detection sensor 12 associated with the rear cover 11 may be used. Since the position where the rear cover 11 does not swing is known in advance, the value may be used. (5) As a method for detecting whether or not the tilling device 4 is separated from the ground surface, a sensor for detecting the driving force of the tilling device 4 is provided. At the point when you leave. (6) As a control form corresponding to the second embodiment, in addition to the case of normal position control, the following forced lifting control can be applied. In other words, the rotary tilling apparatus 4 is provided with an elevating switch 19 (push-on push-off type) for raising the rotary tilling device 4 to a predetermined height with respect to the body at a stretch.
The electromagnetic proportional control valve V1 for raising and lowering is operated prior to the position control means and the automatic plowing depth control means, and the tilling apparatus 4 is raised at a stroke to a predetermined height with respect to the body. When the push operation is performed once again, the tillage device 4 is lowered to the original position, and returns to the state of the position control means or the automatic plowing depth control means. In this case, when raising and lowering the tilling device 4 by pushing the raising / lowering switch 19 to perform the raising operation, when the tilling device 4 is raised above the ground surface, the gradual raising operation is performed.

In the claims, reference numerals are provided to facilitate comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[Brief description of the drawings]

FIG. 1 is a side view showing the rear part of an agricultural tractor.

FIG. 2 is a control configuration diagram.

FIG. 3 is a flow chart showing selection of a target flow rate to the lifting cylinder when shifting from the plowing depth control to the position control.

FIG. 4 is a graph showing the internal pressure of the lifting cylinder with respect to the height of the working device.

FIG. 5 is a graph showing a target flow rate at which the working device is raised from a low position, and FIG.

FIG. 6 is a graph showing a target flow rate at which the working device is raised from the intermediate position, and the internal pressure at the start of the rising at this time is shown in FIG.

FIG. 7 is a graph showing a target flow rate at which the working device is raised from a high position, and FIG.

FIG. 8 is a circuit for detecting a short-circuit of the electromagnetic proportional control valve.

FIG. 9 shows a voltage characteristic when a normal operation is performed.

FIG. 10 shows a voltage characteristic when a short circuit occurs.

FIG. 11 is a side view showing a state in which no cultivation pit is formed when the working device is moved up and down by slow operation.

FIG. 12 is a flowchart illustrating a control mode when shifting from tillage depth control to position control.

FIG. 13 shows the target flow rate in FIG.
Graph showing the state where shock occurs when only the same flow rate as shown in

[Explanation of symbols]

 3 3-point link mechanism 4 Ground work equipment 9 Position setting device CY1 Lift cylinder

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) A01B 63/10-63/114

Claims (1)

(57) [Claims] 1. A ground working device (4) is mounted on a traveling machine body via a three-point link mechanism (3), and the link mechanism (3) is driven by a lift cylinder (CY1) to provide the ground working device (4). 4) A lifting / lowering control device for a working device of an agricultural tractor configured to be capable of raising / lowering operation, wherein a supply means for supplying oil to the lift cylinder (CY1) is provided, and an oil supply amount per unit time by the supply means is provided. ,
An ascent / descent control device for an agricultural tractor working device provided with an adjusting means for reducing the rising start position of the ground working device (4) when the starting position is at a higher position than when the starting position is at a lower position.